1. The Field of the Invention
Exemplary embodiments of the invention relate to the field of mountain and rock climbing. More particularly, the invention relates to belay devices and systems for controlling the ascent or descent of a climber, and methods for using the same.
2. The Relevant Technology
Mountain and rock climbing is a challenging endeavor in which an individual can ascend or descend a rock face that is often close to vertical. At the start of such a climb, the individual chooses a path that will be taken to ascend or descend the face. Particularly for ascending a rock face, the individual must use his entire body, as well as various pieces of specialized equipment. For example, the individual may use specially designed ropes, harnesses, carabiners, shoes, and the like.
Frequently, the climber is not alone when climbing the rock. The safety of the climber can be enhanced by climbing in teams. When climbing as a team, the climber may tie the special climbing rope to a harness worn by the climber, while the other team member belays the climber. As a climber ascends the rock, for example, the belaying partner controls the tension in the rope. The belaying partner can control this tension either by letting out rope or taking rope up to maintain a proper tension in the rope. This tension is important if a climber falls as the greater the tautness or tension in the rope, the less of a distance the climber can fall.
Various belaying systems can be employed. For example, a top-roping belay system uses an anchor that is placed at the top of the rock. The climber's rope extends through the anchor, and the anchor acts as a pulley. The belaying partner may stand at the top of the cliff to belay the climber, although the partner typically stands at the foot of the rock. In either case, the anchor remains at the top of the rock and the rope extends downward toward the climber from above while the partner controls the tension to ensure that the climber will not fall any great distance if he loses his footing or grip on the mountain.
Another belaying system is a lead climbing system in which the climber drags the rope up the mountain and the rope is fed to the climber from below. During the ascent, the climber may clip the rope into carabiners which are secured to the rock at various points up the mountain.
Whether the rope is being fed to the climber in a top-rope or lead climbing system, when the climber falls, the belaying partner uses the belay device to grasp and secure the rope. In this manner, the fall of the climber is stopped and the climber is suspended above the ground. The belaying partner can then lower the climber to the ground by gradually allowing rope to extend through the belay device.
These and other types of belay devices are commonly frictional devices that allow large forces applied to a rope to be held by the belaying partner with little effort. In most cases, the large forces are reduced by belay devices based on the Capstan effect. In such a system, the rope is wrapped around a pin to dramatically reduce the required holding force.
Belay devices of this type generally do not allow a belaying partner to secure more than one rock climber. In addition, such devices generally require that the belaying partner exert some stopping force on the rope to prevent the fall. Sometimes, however, it would be beneficial to have a self-locking belay device such that the belayer need not exert any force. For example, this may allow a climber to climb without a partner. In other cases, however, a self-locking device may introduce larger impact forces that are not recommended for certain types of climbing (e.g., ice climbing or traditional climbing). Accordingly, what are desired are devices and systems that allow a belayer to belay multiple climbers at the same time and with a single device, and which is universal to allow selective use between self-locking and non-self locking modes of operation.